PESTICIDE ACTIVITY OF EXTRACTS OF <i>Piper tuberculatum</i> JACQ ON <i>Haematobia irritans</i> L.

Abstract

The search for alternatives to chemicals in the control of agricultural and veterinary arthropods has intensified in recent years. Among the plants in which the extracts present insecticidal potential are Piper tuberculatum, popularly known as monkey pepper. Haematobia irritans (horn fly) ectoparasite of Brazilian cattle raising, causing losses estimated at U $ 865 million per year. The objective of this work was to evaluate the pesticidal activity of different leaf extracts, fruits and stems of P. tuberculatum in adults of H. irritans. Horn flies were collected directly on infested animals with the aid of an entomological network and transferred to the kits of plates which had holes in the middle. The impregnated filter paper method was used, where the dilutions were 1.56; 3.12; 6.25; 12.5; 25 and 50 mg/mL of each extract, all were evaluated in triplicate. The controls used were ethanol and Cipermerina in technical grade at the concentration of 409.5 mg/mL also in triplicate. About 15 specimens were placed in each Petri dish. The reading was performed two hours after the start of the test. Flies with inability to fly were considered dead. For the analysis of the insecticidal efficacy of the vegetal extracts, a lethal concentration (LC) was obtained through the PROBIT test. The extracts that did not present mortality values were not analyzed. The extracts that presented promising insecticidal activity for hornfly control were the ethanol extracts of leaves of P. tuberculatum (61.14 mg/mL), ethanol extracts of stems of P. tuberculatum (6.00 mg/mL), hexane extracts Of P. tuberculatum fruits (136.88 mg/mL), ethyl acetate extracts of P. tuberculatum stems (1.03 mg/mL). P. tuberculatum presented promising results and a more detailed investigation should be carried out to evaluate its application in the future. Keywords: Haematobia irritans; Piper tuberculatum; pest control.